*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}

.a{
    background: gold;
    color: aqua;
    width: 120px;
}

.a h1{
    cursor: pointer;
}

.a h1:hover{
    background-color: aquamarine;
}

.b{
    display: none;
}
.c{
    margin-top: 200px;
}

.c>li{
    display: inline-block;
    width: 50px;
    height: 20px;
    border: 1px solid gold;
    text-align: center;
    line-height: 20px;
    cursor: pointer;
}

.c>li.d{
    background-color: aqua;
    color: aquamarine;
    background-color: skyblue;
}
.e{
    background-color: brown;
    width: 70px;
    height: 20px;
    border: none;
    text-align: center;
    cursor: pointer;
    margin-top: 200px;
}